Adaptive display power management for mobile games

Abstract

In this paper, we show how tone mapping techniques can be used to dynamically increase the image brightness, thus allowing the LCD backlight levels to be reduced. This saves significant power as the majority of the LCD's display power is consumed by its backlight. The Gamma function (or equivalent) can be efficiently implemented in smartphones with minimal resource cost. We describe how we overcame the Gamma function's non-linear nature by using adaptive thresholds to apply different Gamma values to images with differing brightness levels. These adaptive thresholds allow us to save significant amounts of power while preserving the image quality. We implemented our solution on a laptop and two Android smartphones. Finally, we present measured analytical results for two different games (Quake III and Planeshift), and user study results (using Quake III and 60 participants) that shows that we can save up to 68% of the display power without significantly affecting the perceived gameplay quality.